View source: R/wind_functions2.R
| wind.dl_2 | R Documentation |
wind.dl_2 downloads time-series wind data from the Global Forecast System (GFS) of the USA's National Weather Service (NWS) (https://www.ncei.noaa.gov/products/weather-climate-models/global-forecast). Wind data are taken from NOAA/NCEP Global Forecast System (GFS) Atmospheric Model collection. Geospatial resolution is 0.5 degrees (approximately 50 km), and wind is calculated for Earth surface, at 10 m. More metadata information for current data: https://pae-paha.pacioos.hawaii.edu/erddap/griddap/ncep_global.html Historical data are obtained from the official NOAA/NCEI GFS 0.5 degree archive.
wind.dl_2(
time,
lon1,
lon2,
lat1,
lat2,
type = "read-data",
trace = 1,
source = c("auto", "pacioos", "ncei")
)
## S3 method for class 'rWind_series'
x[[i, exact = TRUE]]
time |
a scalar or vector of POSIXt or Date objects or an character which can transformed into those, see example below. There are currently these options at the GFS database for the hours: 00:00 - 03:00 - 06:00 - 09:00 - 12:00 - 15:00 - 18:00 - 21:00 (UTC) (TO). |
lon1 |
Western longitude |
lon2 |
Eastern longitude |
lat1 |
Southern latitude |
lat2 |
Northern latitude |
type |
Output type. "read-data" is selected by default, creating an R object. If you choose "csv", wind.dl create a a CSV file in your work directory named "wind_yyyy_mm_dd_tt.csv". |
trace |
if trace = 1 (by default) track downloaded files |
source |
Data provider. |
x |
object from which to extract element(s). |
i |
indices specifying elements to extract. |
exact |
Controls possible partial matching (not used yet). |
To get the same format as wind.dl, you should run tidy function from
wind.dl_2 output.
The output type is determined by type="csv" or type="read-data". If
type="csv" is selected, the function creates a "wind_yyyy_mm_dd_tt.csv" file
that is downloaded at the work directory. If type="read-data" is selected,
an rWind_series object is created.
With type = "read-data", wind.dl_2() returns an object of
classes rWind_series and list, with one element per requested time.
Each element stores a data frame of U and V wind components (m/s); element
names encode UTC times and the lat_lon attribute stores the shared grid
coordinates in degrees. Extracting a time step with [[ returns an object
of classes rWind and data.frame, with columns time, lat, lon,
ugrd10m, vgrd10m, dir, and speed, as described in wind.dl().
With type = "csv", wind.dl_2() writes one CSV file per time step in the
working directory and returns NULL invisibly.
wind.dl_2 requires two dates that represent the boundaries of the time
lapse to download wind series data.
U and V vector components allow you to create wind averages or tendencies
for each coordinate at the study area. Longitude coordinates are
provided by GFS dataset in 0/360 notation and transformed internally into
-180/180. "dir" denotes where the
wind/sea current is going (toward), not from where is coming. With
source = "auto", dates before the current PacIOOS coverage are requested
from NOAA/NCEI.
Javier Fernández-López (jflopez.bio@gmail.com)
http://www.digital-geography.com/cloud-gis-getting-weather-data/#.WDOWmbV1DCL
https://pae-paha.pacioos.hawaii.edu/erddap/griddap/ncep_global.graph
wind.mean, wind2raster,
wind.dl, as_datetime,
as.POSIXct
# Download two time steps for a small region in southern Iberia
dt <- as.POSIXct(c("2015-02-12 09:00:00", "2015-02-12 12:00:00"),
tz = "UTC")
ww <- wind.dl_2(dt, -7, -4, 34.5, 37.5)
tidy(ww)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.